1. Field of the Invention
The present invention relates to a fuel injection control system which provides an additional air-fuel ratio feedback control for an electronically controlled fuel injection system.
2. Description of the Prior Art
Fuel injection systems are known in the art in which the amount of air drawn into an engine is measured, and the amount of fuel predetermined in relation to the measured air quantity is programmed in terms of the injection time of electromagnetic valves, whereby the fuel injection quantity is regulated in accordance with the program.
A disadvantage of fuel injection systems of this type is that while various engine parameters such as the intake manifold vacuum and engine temperatures may be detected to control the fuel injection quantity, it is extremely difficult to correct for constantly changing operating conditions of the engine, the variations according to the type of engine, i.e., the variations with different engines, etc., and this particularly gives rise to serious difficulties when the vehicle is equipped with a catalytic exhaust gas cleaning system or the like for exhaust emission control purposes.